Advertisements
Advertisements
Question
The magnification produced when an object is placed at a distance of 20 cm from a spherical mirror is +1/2. Where should the object be placed to reduce the magnification to +1/3.
Solution
- We know that magnification (M) is given by the formula: M = -v/u, where v is the image distance and u is the object distance.
- We are given that M = +1/2 and u = -20 cm (since the object is placed in front of the mirror). Substituting these values into the formula, we get: +1/2 = -v/-20. Solving for v, we find v = +10 cm.
- Now, we need to find the new object distance (u') to achieve a magnification of +1/3. Using the same formula, we have: +1/3 = -v/u'. We know that v remains the same (v = +10 cm). Therefore, we can solve for u': +1/3 = -10/u'. Solving for u', we get u' = -30 cm.
- The object should be moved from its initial position of -20 cm to a new position of -30 cm.
APPEARS IN
RELATED QUESTIONS
A divergent lens of focal length 30 cm forms the image of an object of size 6 cm on the same side as the object at a distance of 15 cm from its optical centre. Use lens formula to determine the distance of the object from the lens and the size of the image formed.
An object of height 4 cm is placed at a distance of 20 cm from a concave lens of focal length 10 cm. Use lens formula to determine the position of the image formed.
The image of a candle flame placed at a distance of 30 cm from a spherical lens is formed on a screen placed on the other side of the lens at a distance of 60 cm from the optical centre of the lens. Identify the type of lens and calculate its focal length. If the height of the flame is 3 cm, find the height of its image.
A student wants to project the image of a candle flame on a screen 60 cm in front of a mirror by keeping the flame at a distance of 15 cm from its pole.
(a) Write the type of mirror he should use.
(b) Find the linear magnification of the image produced.
(c) What is the distance between the object and its image?
(d) Draw a ray diagram to show the image formation in this case.
A concave mirror produces magnification of +4. The object is placed:
(a) at the focus
(b) between focus and centre of curvature
(c) between focus and pole
(d) between the centre of curvature
Explain what is meant by a virtual, magnified image.
The lens A produces a magnification of, − 0.6 whereas lens B produces a magnification of + 0.6.
What is the nature of lens A?
Give scientific reason.
Simple microscope is used for watch repairs.
In a reading glass what is the position of the object with respect to the convex lens used?
Write an expression for magnification for a lens, explaining the meaning of the symbols used.
